Production method of lithium batteries

ABSTRACT

Electrochemical active cathode layers (MoO 3 , FeS 2 ) are produced on the substrate of stainless steel, aluminum, or titanium by the method of thermal vacuum condensation-solidification. This method enables formation of active cathode layer in the wide thickness range of 0.5 μm-3.0 mm.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Ukrainian Application No.2003077004 filed on Jul. 25, 2003 now Patent No. 67135 issued on Jun.15, 2004, and Ukrainian Application No. 20031213443 filed on Dec. 31,2003; the entirety of which is incorporated herein by reference.

This invention relates to chemical power sources and more particularlyto those with lithium-based anode, non-aqueous electrolyte and cathodewhere metal oxides or sulfides are used as an active cathode substance.

Specific discharge characteristics of lithium power sources withsolid-phase cathode, to a great extent, depend on the cathodeproperties, in particular, its specific discharge capacity per weightand volume unit. There are the known lithium power sources with thecathode mass comprising active substance, conducting additive, forexample, graphite and/or black and a binder. Cathode mass is preparedfrom the powders of these components [1].

From the above cathode mass components only active substance iselectrochemically active. The conducting additive provides sufficientelectronic conductivity in cathode mass volume. A binder providesmechanical strength of cathode mass. It should be noted that mechanicalstrength is needed both at power source assembly and in the process ofits operation. It is connected with the fact that at discharging cathodemass volume increases, and decreases at charging. As a result,mechanical stress can appear and lead to electrode destruction. Thebinder should provide mechanical strength of cathode at the all stagesof its work.

Difficulties in the production of dispersion particle and cathodematerial component homogeneous distribution at mechanical mixing is thedisadvantage of the method. In addition, availability of ballastelectrochemically passive material in the composition of positiveelectrode active mass (conducting and binding additives) decreasesgreatly specific electrical characteristics of the produced powersource.

It is known the production method of the ballast-free cathode based onmolybdenum oxide of non-stoichiometric compound intended for the work inlow temperature lithium secondary batteries. The method consists incathode deposition of molybdenum oxides on a current collector fromammonium molybdate solutions [2].

Need for the tight control of electrolysis mode parameters, electrolytecomposition, low production rate of electrochemically active cathodesubstance with the necessary thickness and impossible production ofmolybdenum oxide with the layer thickness (about 1 mm) should beconsidered as the disadvantages of the method. Besides, before powersource assembly with the cathode manufactured by this method, the needfor its long thermal treatment aimed at water residue removal fromelectrode structure appears.

It is known the production method of non-ballast cathode based ontitanium disulfide. At this method cathode layer formation occurs from agaseous phase. In its turn, in the gaseous phase chemical reactionproceeds between titanium chloride and hydrogen sulfide. The interactionproduct (titanium disulfide) is deposited on a current collector as athin film with the thickness ranging from 1 to 10 μm [3].

High toxicity of hydrogen sulfide which is one of the reagents forcathode material synthesis should be considered as the disadvantages ofthis method. Besides, this technological process does not allow toproduce cathode material films with the thickness up to 1 mm, thatdecreases significantly the range of application and possibilities ofchemical power source design.

Production method of the ballast-free active cathode material based onMoO₃ by the anodic oxidation of high purity (99.98%) sheet molybdenum inthe electrolyte comprising 1 M tartrate sodium, 0.13 M tartaric acid and0.01 M sodium carbonate at 2.4 mA/cm² current density and roomtemperature is the closest to the technical solution proposed by theauthors [3].

High value of high-purity molybdenum, low production rate andindeterminacy of the main physical parameters of electrochemicallyactive cathode layer (thickness, specific weight, etc) and impossibilityto produce MoO₃ thick layers (about 1 mm) should be considered as thedisadvantages of the prototype. Besides, before assembly of the powersources with the cathode manufactured by the method, the necessity ofits long thermal treatment aimed at water residue removal from electrodestructure arises.

Design of the power source where increasing specific energycharacteristics is achieved at the cost of the additional amount ofelectrochemically active mass substituting binder and conductingadditive is the task of this invention.

Solving the set task is achieved at the cost of the fact that in theproduction method of lithium battery comprising active cathode massapplied on a current collector, anode, separator and non-aqueouselectrolyte, according to the invention, the cathode mass contains 100%electrochemical active material in the form of metal oxides or sulfidesas a compact deposit. In this case cathode mass density is 2.6-4.9g/cm³, and cathode active layer thickness is selected within the range0.002-1.5 mm. Lithium alloys, carbon or any other compounds reversiblein lithium cations are used as an anode material.

Active cathode material is produced as a compact deposit, consisting ofmolybdenum trioxide (MoO₃) in one case, and in another, of iron sulfide,mainly, of FeS₂-pyrite. In this case cathode provides bending withoutcontact fault between active mass and current collector in the bendingradius range 0.4-3.9 mm at the layer thickness of active cathodematerial ranging from 4 μm up to 440 μm.

Besides, new useful properties are added to the invention, if thespecific weight of cathode material active layer and its structure arechanged in the direction from the current collector/active cathodematerial interface to the cathode active material/non-aqueouselectrolyte interface so that at the current collector/active cathodematerial interface, active material density is higher than that at theactive material/liquid electrolyte interface, in this case the densitycan change by the value 2 g/cm³ in the thickness of electrochemicallyactive metal oxide layer up to 1.4 mm. Active material specific weightdecrease in the direction of the electrode/electrolyte interfacepromotes increasing porosity and material specific surface at theelectrode/electrolyte interface. This adds to the object a new usefuleffect consisting in the fact that at the same geometric currentdensity, the actual current density at the electrode/electrolyteinterface decreases, i.e. electrochemical process occurs in cathodevolume. This indicates electrode effective work at the increasedgeometrical densities of discharging current.

Increasing cathode material porosity at the boundary with electrolytealso contributes to the optimization of the electrode/solid electrolytestructure. Solid inorganic electrolyte is applied on electrode by themethod including the stage of material transition from a gas to a liquidstage, then to a solid one. At the stage of solid electrolyte materialtransition from a gas to liquid stage, the electrolyte penetrates intothe pores of cathode materials and uniformly distributes in electrodevolume. In this case, the high mechanical strength of theelectrode/electrolyte interface is the additional positive property ofthe formed structure.

The metal with a developed surface is used as a cathode currentcollector. Stainless steel, aluminum or titanium are used as the currentcollector material.

In the process of MoO₃ application, temperature of cathode currentcollector ranges from 210 up to 250° C. AT LAYER COOLING RATE FROM 18 upto 22° C./s. In the process of FeS₂ application in the presence ofsulfur vapors, cathode current collector temperature ranges from 20 upto 60° C. Produced by such a method oxide or sulfide cathode is used inprimary and secondary power sources.

In the deposition process of thin (more 80 μm) layers of MoO₃ forprimary power sources, cathode current collector temperature ranges from230 up to 270° C. at the cooling rate of layer 2-4° C./s. In this casethe metal with a developed surface is used as a cathode currentcollector. For example, it may be the metal foil on which surface thepowder of the same metal with the different dispersity is applied.

Enumeration of figures: FIG. 1. Change of the specific capacity ofFeS₂-based cathode depending on a number of charge-discharge cycles.Curve with triangular points corresponds to a discharge. Curve withround points corresponds to a charge. FIG. 2. Dependence of specificdischarge capacity on cathode material thickness. Line with transparentpoints corresponds to the discharge current density up to 0.8 mA/cm².Line with black points corresponds to the discharge current density of 5mA/cm². FIG. 3. Circuit of the prototypes of the disc design microbattery based on MoO₃, produced by the method of thermal vacuumcondensation-solidification. FIG. 4. Circuit of the prototypes ofprismatic design micro battery with the MoO₃,-based cathode produced bythe method of thermal vacuum condensation-solidification. FIG. 5.Investigation of the mechanical strength, adhesion and cohesion ofelectrodes based on molybdenum oxides. FIG. 6. Dependence of MoO₃structure amorphism on electrode thickness. FIG. 7. Change of thespecific weight of MoO₃ in the cathode thickness produced by the methodof thermal vacuum condensation-solidification in the cathode thickness.FIG. 8. Change of the specific electronic conductivity of MoO₃ layerdepending on the electrode discharging degree.

In lithium battery the following electrolytes are used as non-aqueousones:

-   -   1. Liquid electrolyte    -   2. Polymer electrolyte    -   3. Solid inorganic electrolyte.

All electrolytes have lithium cation conductivity.

In the 3-d case, cathode surface is covered by the layer of solidelectrolyte which thickness is 2-10 μm. This combination provides suchnew useful properties as raising specific capacity duringelectrochemical cycling. Application of solid electrolyte is realized bya complicated staged evaporation of material followed by staged cooling.

Between the layer of solid electrolyte covering cathode surface andanode there is a separator impregnated with liquid non-aqueouselectrolyte, or polymer electrolyte.

Modification of positive electrode surface by the layer of solidelectrolyte is used for the manufacture of secondary power sources. Atmodification of positive electrode surface by the layer of solidelectrolyte, the reversible electrochemical characteristics ofelectrodes, which active mass thickness ranges from 0.5 to 80 μm,increase.

The above characteristics are reached due to the application of themethod of thermal vacuum condensation-solidification with the optimalrate of applying the active mass of positive electrode and solidelectrolyte for electrode manufacture.

Selection of MoO₃ as a cathode material in chemical power sources, inthis claim is results from the fact that at heating above 600° C. thisoxide trends to pass to a gaseous state without changing its chemicalcomposition [5]. Most of other oxides which is widely used in primarycells and rechargeable lithium power sources does not posses theseproperties. Say, manganese dioxide (MnO₂) at heating above 535° C.before passing to a gaseous state is decomposed into Mn₂O₃. Vanadiumpentoxide (V₂O₅) is also decomposed at heating above 1750° C., beforepassing to gaseous state [6]. Most of metal sulfides shows the tendencyto chemical destruction at heating up to high temperatures. Productionof iron disulfide (FeS₂) as a thin film, which is also presented as acathode material for lithium chemical power sources in this claim, hasbecome possible due to process of thermal vacuum spraying at the sulfurvapors availability in a working chamber. At the thermal evaporation ofFeS₂, the products of iron disulfide decomposition pass to a gaseousstate. In this case the iron compounds which evaporate and pass into thechamber volume, are united in sulfur.

At thermal FeS₂ evaporation, the products of iron disulfidedecomposition pass in a gaseous state. In this case the iron compoundswhich are evaporated and pass into a chamber volume, are united insulfur. The process of FeS₂ spraying in the presence of sulfur vapors,which are introduced additionally into the volume of working chamber,shifts the chemical equilibrium towards iron disulfide formation. FeS₂,formed due to the process is deposited on a substrate, forming the filmof electrode material.

The filed boundary characteristics depend on the following:

1. At the specific weight of positive electrode active mass less than2.6 g/cm³, the volume specific discharge characteristics of cathode andthe power source, as a whole, decrease.

2. Thickness of positive electrode active mass layer of at least 0.5 μmdoes not allow to produce the uniform layer of MoO₃ along the wholesurface of current collector. In this case the material balance ofbattery also deteriorates, since the need of significant decreasing theweight and thickness of current collector appears.

3. For secondary power source the cathode mass thickness of positiveelectrode should not exceed 80 μm, as far as the greater thickness oflayer does not allow to obtain high reversible specific electrochemicalcharacteristics in liquid and polymer electrolytes.

4. In the case of secondary power source, the positive electrode whichsurface is non-modified by the layer of solid electrolyte, ischaracterized by decreased reversible specific electrochemicalcharacteristics effecting negatively on the charge-dischargecharacteristics of power source as a whole.

5. In the case of primary power source, thickness of electrodes, whichdo not contain a binder and conducting additive, reaches 3 mm. Use ofthick electrodes enables considerable increasing specificcharacteristics of power source. This results from the considerableimprovement of the material balance of the cell which is characterizedby the ratio of the active materials of power source and structuralmaterials.

MoO₃ and FeS₂-based cathodes with a high relative density, produced bythe method of thermal vacuum condensation-solidification are proposed asan example in this invention. High cathode mass relative densityprovides the high specific electrical-characteristics of lithium powersource. Useful advantages of this method and cathode produced on itsbase are as follows:

-   -   after cathode production and its storage in dry atmosphere it        does not require thermal treatment aimed at the removal of water        residua from electrode structure.    -   rate of MoO₃-based cathodes produced by the method of thermal        vacuum condensation-solidification (1-30 μm/s) exceeds        considerably the rate of cathode production described in the        analogues and prototype.    -   the produced cathodes have high mechanical strength, in spite of        the fact that a binder is not a part of cathode mass. This        results from a high adhesion between cathode material and        current collector, and between the particles of cathode material        a high cohesion is observed.

The produced cathodes based on molybdenum oxides have such usefulproperty as a low resistance, in spite of the fact that cathode masscomposition does not comprise conductive additive. Therefore, theproduced molybdenum oxide structure has a high electron conductivity.Ions of metals which are present in a deposit structure as a negligibleadmixture [7] provide a high ion conductivity for the electrode layersof MoO₃ produced by the method of thermal vacuumcondensation-solidification metal ions. In this case high electronicconductivity is provided with molybdenum ions of the lower oxidationdegrees [8]. Intercalation of such ions into cathode structure isprovided at the moment of MoO₃ evaporation. Metal molybdenum was used asthe material of evaporator. At the moment of evaporation, a small partof MoO₃ by the reaction of disproportionation interacts with metalmolybdenum with a low oxide formation which molecules comprisemolybdenum ions of the lower oxidation degree. Partially reducedmolybdenum ions from gaseous phase are deposited on thesubstrate-current collector and build in the crystalline structure ofthe main substance (MoO₃) as an admixture, providing high electronicconductivity of cathode deposit.

Quantity of evaporated material, evaporation temperature, time ofevaporation, substrate temperature, rate of substrate cooling, volume ofworking chamber are the main factors effecting on the quality ofelectrode material layer.

The following examples characterize novelty and industrial applicabilityof the claimed invention.

EXAMPLE 1

Stainless steel substrate of 20 mm diameter is placed in a vacuum unitfor material deposition under the condensation-crystallizationconditions. Substrate surface is subjected by sand-blasting with 3-4 μmrelief depth followed by ionic cleaning at the anode voltage 1.5 kV.After working chamber pumping-out up to the residual pressure 10⁻⁵ TORR,MoO₃ powder (10 mg) is transformed into a vaporous state and isdeposited on a substrate. Analysis of the produced coating has shown itslow adhesion to a substrate, as evidenced by the numerous sections ofseparation and cracking. (Table. 1 p. 1).

EXAMPLE 2

In the unit described in Example 1, quantity of the sprayed substanceshas been increased up to 15 mg, and the working chamber volume has beendecreased by 2 times. Evaporation of the initial substance was carriedout at 620° C. Substrate temperature was increased up to 200° C. Time ofspraying is 3 sec. Thus, the conditions necessary for substancecondensation on a substrate as a liquid phase state have been created.Liquid layer of MoO₃ was crystallized with the help of forced cooling byargon jet. Cooling rate was 10° C./sec. Analysis of the produced coatinghas shown that at 8-10 μm thickness it has a good adhesion to asubstrate. Adhesion strength was determined by the minimum radius ofsample bending at which micro cracks reaching a substrate on its surfacewere observed. Analysis of sample cracking was carried out with the helpof scanning electron microscope. Value of the bending radius was 1.2 mm.X-ray diffraction analysis (XRD) of the produced sample has discoveredavailability of MoO₂, MoO₃, Mo₄O₁₁ phases in it. (Table. 1 p. 2).

EXAMPLE 3

In the unit described in Example 2, evaporation temperature of asubstance was increased up to 700° C. Temperature of a substrate was100° C. Cooling temperature after liquid layer condensation wasincreased up to 20° C./sec. Analysis of the produced coating has shown,that in a thickness and adhesive strength it corresponds to its analoguedescribed in Sample 2, however, by the results of XRD analysis it hasamorphous structure. (Table. 1 p. 3).

EXAMPLE 4

In the unit described in Sample 3, coating of initial MoO₃ has beenproduced at substrate temperature 130° C. Analysis of the producedcoating has shown that it is presented as Mo₄O₁₁ compound. (Table. 1 p.4).

EXAMPLE 5

In the unit described in Example 3, the coating of initial MoO₃ has beenproduced from initial MoO₃ at substrate temperature 160° C. XRD analysishas shown that the layer compound corresponds to MoO₂ stoichiometry.(Table. 1 p. 5).

EXAMPLE 6

In the unit described in Example 3, coating of the initial substanceMoO₃ has been produced at substrate temperature 230° C. Analysis of theproduced coating has shown that it has thin differential plasticstructure and corresponds to MoO₃ stoichiometry. (Table. 1 p. 6).

EXAMPLE 7

In the installation described in Example 3 the coating of the initialMoO₃ substance has been produced at substrate temperature 300° C.Deposition time—20 s. In this case the sample is cooled from the side ofsubstrate with the rate 3° C./sec. Thus, the sample with coatingthickness 1.32 mm and the lamellar structure of MoO₃ has been produced.Average specific weight of the produced MoO₃ layer was 2.3 g/cm³.(Table. 1 p. 7).

SAMPLE 8

In the unit described in Example 7, it has been produced a coating ofthe initial substance MoO₃ at substrate temperature 250° C. Thus, thesample with 1.3 mm thickness has been produced with the lamellarstructure of MoO₃. Average specific weight of the produced MoO₃ layerwas COCTaBπ

π 2.73 g/cm³. (Table 1 p. 8).

EXAMPLE 9

In the unit described in Example 3, coating from the initial substanceFeS2 has been produced at substrate temperature 40° C. Working space washeated up to 500° C. Initial substance was evaporated at 750° C. anddeposited on the substrate during 50 sec. The layer mass was 1 mm at thesatisfactory adhesion to a substrate. Phase compound of coating: Fe₉S₈+Smonoclinic.

EXAMPLE 10

In the unit described in Example 8 coating has been produced from theinitial substance FeS₂ at substrate temperature 40° C. However, usingadditional evaporator, sulfur vapor was supplied to operation space at240° C. Evaporation of FeS₂ was carried out at 800° C. Total time ofspraying is 51 s. Mass of the sprayed layer was 1.4 mg. Phase analysisenables detection of the following components in the sprayed layer:Fe₃S₄—basis, Fe₇S₈—up to 5%.

EXAMPLE 11

In the unit, described in Example 9, it has been produced the coating ofthe initial substance FeS₂ at substrate temperature 40° C. Sulfur vaporwas introduced at 150° C. Total time of spraying is 110 seconds. Mass ofthe sprayed layer—4 mg. Phase analysis of coating has shown thefollowing: sulfur (monoclinic)—50%, FeS₂—5%, Fe₃S₄—7%, Fe S—30%, Sorthorhombic—8%.

EXAMPLE 11

In the unit described in Example 10, coating from the initial substanceFeS₂ has been produced at substrate temperature 40° C. Vapor of sulfuris introduced at 190° C. Total time of spraying—50 s. Coating mass—1.8mg. Phase compound of coating—FeS₂ (pyrite)—95%, Fe₂ S (marcasite)—5%.

EXAMPLE 13

Deposition of solid inorganic electrolyte comprising lithium, tungstenand bore oxides was carried out on a thin MoO₃ film produced by the modeof Example 6 with the help of vacuum unit, which supposes condensationof vaporous phase with thin liquid layer formation followed by itscrystallization analogically described in Example 3. Deposition wascarried out under the following conditions: initial material was heatedup to 900° C. for 21 sec and then was kept at this temperature during 4sec. Further, temperature was raised up to 1500° C. for 4 sec., andisothermal holding for 2 sec was carried out. In this case fullevaporation of the initial substance with the mass of 5 mg is observed.After substance condensation as a liquid film on the molybdenum oxidesurface with the help of forced blasting with inert gas during 30 sec.,liquid crystallized. At cooling electrode temperature is decreased from200° C. up to 100° C. Analysis of 3 μm coating produced on molybdenumoxide with the thickness 3 μm has shown availability of the crystallinephases Li₂WO₄, Li₄B₁₀O₁₇. Film structure is coarse-grained, and ischaracterized by the different thickness, which variation reaches morethan 30%. (Table 1, p. 13).

EXAMPLE 14

Deposition of solid inorganic electrolyte comprising lithium, tungstenand bore oxides was carried out on a thin MoO₃ film produced by the modeof Example 6 with the help of vacuum unit, which supposes condensationof vaporous phase with thin liquid layer formation followed by itscrystallization analogically described in Example 3. Deposition wascarried out under the conditions of Example 13 with the followingchanges: initial substance was heated up to 800° C. for 15 sec and thenwas kept at this temperature during 10 sec. Further, evaporatortemperature was raised up to 1000° C. with the rate of 45° C./s.Isothermal holding at this temperature lasted 20 s. Temperature of MoO₃was maintained at the level of 40° C. After substance condensation as aliquid film on molybdenum oxide surface with the help of forced blastingwith inert gas during 30 sec., liquid crystallized. At cooling,electrode temperature is decreased from 200° C. up to 100° C. Analysisof 3 μm coating produced on molybdenum oxide with the thickness 3 μm hasshown availability of the crystalline phases of Li₂WO₄. Analysis of theproduced solid electrolyte film carried out by the method of X-raydiffraction and metal graphic analysis has shown its opticaltransparency and X-ray amorphous structure (Table 1, p. 14).

EXAMPLE 15

Deposition of solid inorganic electrolyte comprising lithium, tungstenand bore oxides was carried out on a thin film of FeS₂, produced underthe conditions of Sample 12 with the help of vacuum plant, whichsupposes the vapour phase condensation with formation of liquid thinlayer and its further crystallization, analogically described in Example3. The deposition was carried out under the following conditions. Theinitial substance was heated up to 1000° C. for 10 s and is kept at thistemperature during 5 sec. Then temperature of evaporator is increased upto 12000° C. for 2 sec with the following isothermal holding for 13 sec.After its finishing the substance is heated up to 1500° C. for 10 sec.,and is held at the same temperature during 3 sec. Thus, total time ofspraying was 43 s. During this time, temperature of FeS2 surface waslinearly increased from 20° C. to 300° C. Cooling of the film formed onFeS₂ surface was carried out similar to Example 13. Analysis of theproduced coating has shown that it has a coarse-crystalline structurewith the phase composition and variation in thickness, similar to Sample13 (Table 1, p. 15).

EXAMPLE 16

Deposition of solid inorganic electrolyte comprising lithium, tungsten,and bore oxides was carried out on a thin FeS₂ film produced under theconditions of Example 12 with the help of vacuum plant, supposingcondensation of vapor phase with formation of thin liquid layer and itsfollowing crystallization similar to that described in Example 3.Deposition was carried out under the conditions of Example 15 with thefollowing changes. Heating of initial substance in evaporator wascarried out by the following method: temperature was increased up to1000° C. for 10 sec., and then after 5-second isothermal holding up to1200° C. for 5 s. At this temperature isothermal holding was 15 s, thentemperature was step-wise increased up to 1500° C. at which the materialwas held for 3 s. Thus, the total time of spraying was 38 s. During thistime temperature of FeS₂ surface linearly increased from 20 up to 300°C. Cooling of the film formed on FeS₂ surface was carried out similarlyto Example 15. Analysis of the produced solid electrolyte film carriedout by the method of X-ray diffraction and metal graphic analysis hasshown its optical transparency and X-ray amorphous structure (Table 1,p. 16). Coating thickness was 4 μm (Table. 1 p. 16).

EXAMPLE 17

Electrode produced in Example 8 is placed to the case of disc designpower source comprising lithium negative electrode and liquid aproticelectrolyte. In this case the surface of current collector, on whichcathode material is applied, is developed. The power source is sealedand tested: its discharge density is measured. At cell discharging, itsspecific discharge capacity per cathode weight unit is 300 mA·h/g. It is819 mA·h/cm³ of cathode. Thickness of such electrode layer is 1.3 mm(Table. 2 p. 3).

EXAMPLE 18

Two electrodes produced under the conditions of Example 8, are placedinto the case of prismatic design power source of laminated aluminumfoil, which comprises lithium negative electrode and liquid aproticelectrolyte. Thickness of layer of one such electrode is 1.4 mm.Specific weight of MoO₃ decreases in the direction from currentcollector, on which oxide layer is applied, to the external surface ofmolybdenum oxide. In actual power source, the external boundary of MoO₃borders with electrolyte. Specific weight of molybdenum oxide decreasesfrom 3.9 g/cm³ up to 2.1 g/cm³ at the boundary with current collector onthe external surface of MoO₃. Power source is sealed and tested: itsdischarge capacity is measured. At discharging specific volume capacityof the cell is 466 mA·h/cm³. In this case cathode discharge capacity perMoO³ weight unity reaches 300 mA·h/g. It is 800 mA·h/cm³ of cathode(Table 2 p. 5).

EXAMPLE 19

Electrode produced in Example 6 is placed into the case of disc orprismatic power source of laminated aluminum foil, comprising lithiumnegative electrode and non-aqueous electrolyte. Power source is sealedand tested—its discharge capacity is measured. At cell dischargingelectrode capacity is 260-300 mA·/g of cathode at the first cycle. Atcharging at the second and following cycles (near 95 charge-dischargecycles) specific capacity ranges from 230 to 90 mA·h/g of cathode. Inthis case cathode layer thickness ranges 0.5-80 μm (Table 2, p. 6, 7).

EXAMPLE 20

Polymer electrolyte solution is poured out on the surface of electrodeproduced in Example 6. Polymer electrolyte film is formed by removinglow-boiling solvent. Having moistened the surface of negative electrodeand polymer electrolyte by liquid aprotic electrolyte, an electrodestructure is assembled. Electrode structure is placed in the case ofcell and sealed. The manufactured cell is tested including themeasurements of its discharge capacity. At cell discharging, electrodedischarge capacity is 200-300 mAh/g of cathode at the first cycle. Atdischarging, at the second and following cycles (up to 120charge-discharge cycles) specific capacity is 230-100 mAh/g. In thiscase cathode layer thickness ranges from 0.5 to 80 μm (Table 2, p. 8,9).

EXAMPLE 21

Electrode manufactured by Example 14 is placed into the case of cell.Separator impregnated with a liquid electrolyte is placed on the filmsurface of solid electrolyte. Assembly of electrode structure iscompleted with negative lithium electrode, then the cell is sealed.Tests of the manufactured cell include the measurements of its dischargecapacity. At cell discharging, electrode discharge capacity is 390mA·h/g of cathode at the first cycle. At discharging, specific capacityranges from 300 up to 140 mA·h/g of cathode at the second and followingcycles (up to 500 charge-discharge cycles). In this case cathode layerthickness is 2 μm (Table 2, p. 10).

EXAMPLE 22

Electrodes produced in Sample 12 is placed into the case of disc orprismatic power source of laminated aluminum foil, which compriseslithium negative electrode and non-aqueous electrolyte. The power sourceis sealed and tested: its discharge capacity is measured. At celldischarging, electrode discharge capacity is 850 mA·h/g of cathode atthe first. At discharging at the second and following cycles theelectrode did not show electrochemical activity (Table 2, p. 11).

EXAMPLE 23

Polymer electrolyte solution is poured out on the surface of electrodeproduced in Example 12. Polymer electrolyte film is formed by removinglow-boiling solvent. Having moistened the surface of negative electrodeand polymer electrolyte by liquid aprotic electrolyte, an electrodestructure is assembled. The electrode structure is placed into the caseof cell and sealed. The manufactured cell is tested including themeasurements of its discharge capacity. At cell discharging, electrodedischarge capacity is 850 mAh/g of cathode at the first cycle. Atdischarging, at the second and following cycles the electrode did notshow electrochemical activity (Table 2, p. 12).

EXAMPLE 24

Electrode, manufactured by the Example 16, is placed into the case ofcell. Separator impregnated with liquid electrolyte is placed on thesurface of solid electrolyte film. Assembly of electrode structure iscompleted by negative lithium electrode, then a cell is sealed. Thetests of the produced electrode include the measurement of its dischargecapacity. At cell discharging, electrode discharge capacity is 850mA·h/g of cathode at the first cycle. At discharging, at the second andthe following cycles (up to 60 charge-discharge cycles) specificcapacity ranges from 450 up to 300 mA·h/g. Change of specific capacitydepending on a number of charge-discharge cycles, where FeS2 system (2μm) is presented as a solid electrolyte (4 μm)—liquid electrolyte—Li isshown in FIG. 1 (Table 2, p. 13).

EXAMPLE 25

For the cathode based on molybdenum oxide, produced by the above method,discharge capacity is independent on the cathode material thickness inthe MoO₃ thickness range 2-1330 μm. Specific discharge capacitydecreases only by 20% at current density increase by 6 times from 0.8mA/cm² to 5.0 mA/cm², as it is shown in FIG. 2.

EXAMPLE 26

MoO₃ layer of the different thickness is applied on some currentcollectors. Then, cathode layer adhesion strength to the currentcollector surface is investigated. The adhesion strength is determinedby the minimum bending radius of the sample when on its surface themicro cracks reaching a substrate appear. Analysis of sample crackingwas carried out with the help of scanning electron microscope. It isevident, that at cathode coating thickness more than 430 μm, radius ofelectrode bending is only 3.9 mm, while its mechanical propertiespreserved. These results have been obtained for the electrodes which donot comprise a binder in the composition of cathode material. Theinvestigation results of mechanical strength, adhesion and cohesion ofthe electrodes based on molybdenum oxides produced by Example 5 areshown in FIG. 5.

EXAMPLE 27

MoO₃ layers of different thickness are applied on some currentcollectors. The dependence of oxide structure amorphizm at thicknessincrease has been discovered by the method of morphological analysis onthe investigation results on scanning electron microscope. Electrodethickness increase is accompanied by MoO₃ amorphism decrease. It is seenin FIG. 6.

EXAMPLE 28

At MoO₃ thickness increase, density of cathode material active layer andits structure change in the direction from the current collector/activematerial interface to the active cathode material/non-aqueouselectrolyte interface so that at the interface current collector/activecathode material, current density of active material is higher than atthe active material/liquid electrolyte interface. In this case, thedensity can change by the value 2 g/cm³ in the thickness ofelectrochemical active layer MoO₃ up to 1,4 mm. Change of MoO₃ specificweight in cathode thickness produced by the method of thermal vacuumcondensation-solidification is presented in FIG. 7.

EXAMPLE 29

Two electrodes produced under the conditions of Sample 8 are placed intothe case of prismatic design power source of laminated aluminum foilcomprising lithium negative electrode and liquid aprotic electrolyte.Thickness of one such layer is 1.3 mm. Specific weight of MoO₃ decreasesin the direction from current collector on which oxide layer is appliedto the external surface of molybdenum oxide. In actual power source theexternal boundary of MoO₃ borders on electrolyte. Specific weight ofmolybdenum oxide decreases from 3.9 g/cm³ at the boundary with currentcollector up to 2.1 g/cm³ on the external surface of MoO₃. Power sourceis sealed and tested: discharging by 10% of the nominal dischargecapacity by the current at which cathode current density is 0.45 mA/cm²,is held in the disconnected state during one day, after that itsimpedance characteristics are investigated with the help of electrodeimpedance method. From the spectrum presented on the R−1/w·Ccoordinates, electron component is calculated, which resistance almostfully relates to the cathode layer of MoO₃. It has been established thatspecific electron conductivity (G_(e)) of electrode layer based on MoO₃,linearly increases in the first third of discharge capacity from3.5·10⁻³ Ω⁻¹·cm⁻¹ up to 1.2·10⁻² Ω⁻¹·cm⁻¹, after that it slightlydepends on the discharge degree. Change of specific electronconductivity of MoO₃ layer on the electrode discharge degree ispresented in FIG. 8.

EXAMPLE 30

Power source prototype is manufactured by such a way. Cathode based onmolybdenum oxide has been produced by the method of thermal vacuumcondensation-solidification, described in Example 6. Thickness of MoO₃layer ranges from 30 up to 170 μm. Specific weight of MoO₃ layer ranges3.0 up to 3.6 g/cm³. Molybdenum oxide is applied on aluminum foilcurrent collector with the thickness 20 μm covered with the layer ofsolid inorganic electrolyte produced by Example 13. Solid electrolytethickness is 4 μm. Lithium anode is also produced by the method ofthermal vacuum condensation-solidification. Lithium anode thickness isabout 55 μm. Copper foil of the 10 μm thickness is used as a currentcollector for lithium anode. Discharge cathode capacity is near 360mA·h/g. Operation current density is up to 5 mA/cm² (Table. 2 p. 14).

EXAMPLE 31

Prototype of prismatic primary lithium power source with liquidelectrolyte has been produced on the basis of MoO₃, obtained by theExample 8. The cell comprises the following components: two cathodesbased on MoO₃, produced by condensation-solidification method. Averagespecific weight of cathode material is 2.66 g/cm³. Cathode materialthickness on one MoO₃—electrode is 1.25 mm. Geometrical size ofelectrodes is 2×(1.5×1.5) cm. Aluminum foil with the developed surfaceand 20 μm thickness is used as a cathode current collector. Separatorthickness—25 μm. Discharge current—2 mA. Before testing, the powersources was stored for 4 months. Discharge capacity of cell is 475 mAh.Specific capacity of cathode is 317 mA·h/g. It is 843 mA·h/cm³. Specificpower per electrode structure volume is 1307 Wt·h/l (Table 2, p. 15).

EXAMPLE 32

Prototype of prismatic secondary power source based on MoO₃, has beenproduced by Example 8. The power source comprises the followingcomponents: two cathodes based on molybdenum oxide produced by themethod of condensation-solidification. Average specific weight ofcathode material is 3.66 g/cm³. Thickness of MoO₃ layer on cathode is—85μm. Electrode geometry size is 2×(1.2×1.2) cm. Aluminum foil with the 20μm thickness is used as a current collector. Cathode is covered by thelayer of inorganic electrolyte with 5 μm thickness. At room temperaturesolid inorganic electrolyte has specific conductivity in lithium cations10⁻⁵ Cm/cm. Solid inorganic electrolyte was applied by the method ofthermal vacuum condensation-solidification by Example 14. Separator with25 μm thickness was impregnated with liquid non-aqueous electrolyte.Metal lithium was used as an anode. The cell was tested under thefollowing conditions: discharge current—0.3 mA; charge current—0.15 mA.Before testing the element was stored for two months. Results of celltesting are as follows: discharge capacity—27 mA·h; specific capacity ofcathode—305 mA·h/g. Specific volume energy per electrode structure is870 mA·h/dm³ (Table 2 p. 16).

EXAMPLE 33

Electrode produced in Example 7 is placed into the case of dick designpower source comprising lithium negative electrode and liquid aproticelectrolyte. In this case surface of current collector, on which cathodematerial was applied, is developed. Power source is sealed andtested—its discharge capacity is measured. At cell discharging, cathodedischarge capacity reaches 300 mA·h/g. It constitutes 690 mA·h/cm³ ofcathode. MoO₃ electrode layer thickness is 1.32 mm (Table 2 p. 1).

EXAMPLE 34

Electrode produced in Example 8 is placed into the case of dick-designpower source comprising lithium negative electrode and liquid aproticelectrolyte. In this case current collector surface, on which cathodematerial is applied, is smooth. Thickness of such electrode is 1.3 1.3mm. MoO₃ separated from the smooth surface of current collector evenafter insignificant shaking (Table 2 p. 2).

EXAMPLE 35

Two electrodes produced under the conditions of Sample 7, are placedinto the case of prismatic design power source of laminated aluminumfoil, comprising lithium negative electrode and liquid aproticelectrolyte. Layer thickness of one electrode is 0.9 mm, and another oneis 1.0 mm. Average specific weight of MoO₃— cathode is 1.5 g/cm³. Powersource is sealed and tested (measurement of its discharge capacity). Atcell discharging, cathode specific discharge capacity is 300 mA·h/g. Inthis case volume capacity of cathode is 450 mA·h/cm³. (Table 2, p. 4).

The battery designs presented in FIGS. 3 and 4 are the evidence ofusefulness and industrial applicability of the proposed invention. Thedisc design battery (FIG. 3), consists of 1—cell case. 2—cathode currentcollector. 3—cathode. 4—anode current collector. 5—anode (metal lithium.6—separator. 7—cover. 8—poly propylene gasket. Prismatic design battery,presented in FIG. 4 consists of 1—Case of cell case. 2—Cathode currentcollector. 3—Cathode. 4—Anode current collector. 5—Anode (metallithium). 6—Separator. 7—Welds.

The above examples are illustrated by the results presented in Tables 1,2.

REFERENCES

-   1. I. A. Kedrinsky, V. E. Dmitrenko, Yu. M. Povarov, and I. I.    Grudyanov. Chemical power sources with lithium    electrode.—Krasnoyarsk: Krasnoyarsk university, 1983, P. 95.-   2. V. M. Nagimy, R. D. Apostolova, A. S. Baskevich, and E. M.    Shembel. Electrolytical production of molybdenum oxides//Zhurnal    prikladnoy khimii 2000, No 3, P. 406-409.-   3. U.S. Pat. No. 4,572,873/Feb. 25, 1986/.Kanehori et al.-   4. I. S. Vereschagin, K. I. Tikhonov, and A. L. Rotinyan.    Electrochemical behavior of molybdenym oxide films in propylene    carbonate//Elektrokhimiya.—1981—V. 17.—No 5. P. 783-787.-   5. Molybdenum. Collection. Foreign Literature Publishing, Ed. A. K.    Natanson. Moscow, 1959, P. 304.-   6. Brief reference book of chemist. Ed. 6, M, 1963.-   7. V. A. Dubok, E. S. Kotenko. Chemistry and physics of    semiconductors. Kiev, <<Vyscha Shkola”>>, 1973, P. 287.-   8. G. V. Samsonov, T. G. Bulankova, A. L. Burykina, et al. Physical    and chemical properties of oxides. <<Metallurgy>>, 1969, P. 273.

SHORT DESCRIPTION OF THE DRAWINGS

FIG. 1. Change of the specific capacity of FeS₂-based cathode dependingon a number of charge-discharge cycles. Curve with triangular pointscorresponds to a discharge. Curve with round points corresponds to acharge.

FIG. 2. Dependence of specific discharge capacity on cathode materialthickness. Line with transparent points corresponds to the dischargecurrent density up to 0.8 mA/cm². Line with black points corresponds tothe discharge current density of 5 mA/cm².

FIG. 3. Circuit of the prototypes of the disc design micro battery basedon MoO₃, produced by the method of thermal vacuumcondensation-solidification.

FIG. 4. Circuit of the prototypes of prismatic design micro battery withthe MoO₃,-based cathode produced by the method of thermal vacuumcondensation-solidification.

FIG. 5. Investigation of the mechanical strength, adhesion and cohesionof electrodes based on molybdenum oxides.

FIG. 6. Dependence of MoO₃ structure amorphism on electrode thickness.

FIG. 7. Change of the specific weight of MoO₃ in the cathode thicknessproduced by the method of thermal vacuum condensation-solidification inthe cathode thickness.

FIG. 8. Change of the specific electronic conductivity of MoO₃ layerdepending on the electrode discharging degree. TABLE 1 Evapo- No Weightof ration Evapo- Substrate Rate of Volume Material Ex- evaporatedtemper- ration temper- substrate of adhesion am- substance, ature, timeature cooling, working to ple Γ ° C. sec. ° C. ° C./sec chamber Otherconditions substrate XRD-analysis Note 1 10 · 10⁻³ 650 3 20 2 x — Weakamorphous- Weak adhesion crystalline relative to (Mo₄O₁₁) substrate 2 15· 10⁻³ 620 3 200 10 x/2 — Good MoO₂, MoO₃, Low MoO₃ Mo₄O₁₁ content inactive mass 3 15 · 10⁻³ 700 3 100 20 x/2 — Good Amorphous Low structureelectrochemical characteristics 4 15 · 10⁻³ 700 3 130 20 x/2 — WeakMo₄O₁₁ Low electrochemical characteristics 5 15 · 10⁻³ 700 3 160 20 x/2— Weak MoO₂ MoO₃ unavailability 6 15 · 10⁻³ 700 3 230 20 x/2 — Good MoO₃Claimed conditions 7 0.9 700 20 300 3 x/2 — Good MoO₃ Low specificweight of MoO₃ 8 0.91 700 20 250 3 x/2 — Good MoO₃ Claimed conditions 915 · 10⁻³ 750 50 40 — x/2 Temperature Good Fe₉S₈ + S FeS₂-pyrite ofworking monoclinic unavailability space - 500° C. 10 15 · 10⁻³ 800 51 40— x/2 Temperature Good Fe₃S₄ + Fe₇S₈ FeS₂-pyrite of workingunavailability space 240° C., sulfur vapors availability 11 15 · 10⁻³800 110 40 — x/2 Temperature Good Monoclinic + Low-content of workingorthorhombic, FeS₂-pyrite space FeS₂, Fe₃S₄, FeS 150° C., sulfur vaporavailability 12 15 · 10⁻³ 800 50 40 — x/2 Temperature Good FeS₂-pyrite(95%) + Claimed of working FeS₂- conditions space marcasite 190° C.,sulfur vapor availability 13  5 · 10⁻³ 900/1500 31 200 3.3 x/2 Stageheating Good Inclusions of the Low quality of at substance crystallinesolid electrolyte evaporation phases of film Li₂WO₄, Li₄B₁₀O₁₇,coarse-grained film of different thickness 14  5 · 10⁻³ 800/1000 50 40 —x/2 Staggered Good X-ray Claimed heating at amorphous, conditionssubstance optically evaporation transparent film 15  5 · 10⁻³ 1000/1200/43 20/300 3.3 x/2 Staggered Good Coarse-grained Low quality of 1500heating at crystalline solid electrolyte substance film of filmevaporation different thickness 16  5 · 10⁻³ 1000/1200/ 38 20/300 — x/2Staggered Good X-ray Claimed 1500 heating at amorphous, conditionssubstance optically evaporation transparent film

TABLE 2 Specific Discharge cathode No Cathode weight of capacity, mA ·h/g/ Ex- Evapo- thick- cathode Surface of mA · h/c3³ am- rated ness,layer, Design of current 1^(st) 10-th 30-th 100-

No ple material μm g/cm³ cell case collector Electrolyte cycle cyclecycle

Note 1 33 MoO₃ 1320 2.3 Disc Developed Liquid 300/ — — — Low discharge690 capacity. Cathode specific weight is lower than the below claimedconditions 2 34 MoO₃ 1300 2.8 Disc Smooth Liquid — — — — Cathodespalling from current collector. Non-execution of claimed conditions 317 MoO₃ 1300 2.73 Disc Developed Liquid 300/ — — — Claimed properties of819 the cell. 4 35 MoO₃ 1900 1.5 Prismatic Developed Liquid 300/ — — —Low discharge 450 capacity. Cathode specific weight is lower than theclaimed conditions 5 18 MoO₃ 1400/ 2.1-3.9 Prismatic Developed Liquid300/ — — — Claimed properties of 1400 800 a cell 6 19 MoO₃ 2.5 3.2 DiscSmooth Liquid 260 182 151 121 Claimed properties of a cell 7 19 MoO₃ 253.28 Disc Smooth Liquid 300 113  90 — Claimed properties of a cell. 8 20MoO₃ 2 3.2 Disc Smooth Polymer 284 166 126 100 Claimed properties of acell. 9 20 MoO₃ 11 3.2 Disc Smooth Polymer 313 134 100 — Claimedproperties of a cell. 10 21 MoO₃ 2 3.2 Disc Smooth Solid/ 390 240 200140 Claimed properties of liquid a cell 11 22 FeS₂ 2 4.5 Disc SmoothLiquid 850 — — — Low reversible electrochemical characteristics 12 23FeS₂ 2 4.5 Disc Smooth Polymer 850 — — — Low reversible electrochemicalcharacteristics 13 24 FeS₂ 2 4.5 Disc Smooth Solid/ 850 328 322 175Claimed properties of Liquid a cell 14 30 MoO₃ 30-170 3.0-3.6 PrismaticSmooth Solid/ 360 — — — Claimed properties of Liquid a cell. 15 31 MoO₃1250 2.66 Prismatic Developed Liquid 317/ — — — Claimed properties of843 a cell 16 32 MoO₃ 85 3.66 Prismatic Smooth Solid/ 305/ — — — Claimedproperties of Liquid 1116 a cell.

1. Production method of lithium battery comprising active cathode massapplied on a current collector, anode, separator and non-aqueouselectrolyte, according to the invention, the cathode mass contains 100%electrochemical active material in the form of metal oxides or sulfidesas a compact deposit. In this case cathode mass density is 2.6-4.9g/cm³, and the cathode active layer thickness is selected within therange from 0.5 μm to-3 mm.
 2. Production method of lithium battery at p.1 is characterized by the following lithium alloys, carbon or any othercompounds reversible in lithium cations are used as an anode material.3. Production method of lithium battery at p. 1 is characterized by thefollowing active cathode material is produced as a compact deposit,consisting of molybdenum trioxide (MoO₃) in one case, and in another, ofiron sulfide, mainly, of FeS₂-pyrite.
 4. Production method of lithiumbattery at p. 1 is characterized by the following cathode providesbending without contact fault between active mass and current collectorin the range bending radius 0.4-3.9 mm at the layer thickness of activecathode material ranging from 4 μm up to 440 μm
 5. Production method oflithium battery at p. 1 is characterized by the following Active cathodematerial is produced as a compact deposit consiting of iron sulfides 6.Production method of lithium battery at p. 1 is characterized by thefollowing current density of cathode active material and its structureare changed in the direction from the current collector/active cathodematerial interface to the cathode active material/non-aqueouselectrolyte interface so that at the current collector/active cathodematerial interface, active material density is higher than that at theactive material/liquid electrolyte interface, in this case the densitycan change by the value 2 g/cm³ in the thickness of electrochemicallyactive metal oxide layer up to 1.4 mm.
 7. Production method of lithiumbattery at p. 1 is characterized by the following cathode activematerial is applied on the surface of current collector by the method ofthermal vacuum condensation-solidification.
 8. Production method oflithium battery at p. 1 is characterized by the following in the processof cathode production molybdenum evaporator is used.
 9. Productionmethod of lithium battery at p. 1 is characterized by the followingstainless steel, aluminum or titanium are used as a current collector.10. Production method of lithium battery at p. 4 is characterized by thefollowing in the process of MoO3 deposition temperature of cathodecurrent collector ranges from 210 to 250*C at the cooling rate from 18up to 22*C/s
 11. Production method of lithium battery at p. 10 ischaracterized by the following the produced cathode is used in primaryand secondary power sources
 12. Production method of lithium battery atp. 5 is characterized by the following in the process of FeS2application in the presence of sulfur vapors temperature of cathodecurrent collector ranges from 20 to 60*C
 13. Production method oflithium battery at p. 1 is characterized by the following metal withdeveloped surface is used as a cathode current collector
 14. Productionmethod of lithium battery at p. 11 is characterized by the following inthe process of MoO3 application temperature of cathode current collectorranges from 230 to 270*C at the cooling rate of layer 2-4*C/s 15.Production method of lithium battery at p. 14 is characterized by thefollowing the produced cathode is used in in primary power sources. 16.Production method of lithium battery at p. 1 is characterized by thefollowing liquid electrolyte is used in primary power sources 17.Production method of lithium battery at p. 1 is characterized by thefollowing polymer electrolyte with lithium cation conductivity is usedas a non-aqueous electrolyte
 18. Production method of lithium battery atp. 1 is characterized by the following solid inorganic electrolyte withlithium cation conductivity is used as non-aqueous electrolyte 19.Production method of lithium battery at p. 1 is characterized by thefollowing cathode surface is covered with solid electrolyte layer 20.Production method of lithium battery at p. 1 is characterized by thefollowing at the stage of solid electrolyte transfer from a gas intoliquid phase, electrolyte penetrates into cathode material pores and isuniformly distributed in electrode volume
 21. Production method oflithium battery at p. 1 is characterized by the following thickness ofsolid electrolyte layer is 2-10 μm, and the process of solid electrolytedeposition is realized by the following step-like deposit cooling 22.Production method of lithium battery at p. 1 is characterized by thefollowing separator impregnated with a liquid non-aqueous electrolyte isbetween the lasyer of solid electrolyte.
 23. Production method oflithium battery at p. 1 is characterized by the following polymerelectrolyte with lithium cation conductivity is between the layer ofsolid electrolyte covering cathode surface and anode.
 24. Productionmethod of lithium battery at p. 1 is characterized by the followingseparator impregnated with liquid non-aqueous electrolyte is between thelayer of polymer electrolyte covering cathode surface and lithium anode.